Groove Velocity and/or Duration Groove Velocity and/or Duration only takes effect when you quantize to a track or select the Groove named: button and choose a Metro Groove from the pop-up menu. The Groove Velocity or Duration percentage specifies how much of the original Metro Groove’s velocity and/or duration you want applied to the currently selected notes. Entering a value of 100% field replaces the velocities and/or durations of the selected notes with the values of the specified Metro Groove; entering a value of 0% specifies not to change velocities and/or durations at all.